Radio receiver tuning control mechanism



Aug. 11, 1936.

E. H. BICKLEY 2,050,555

RADIO RECEIVER TUNING CONTROL MECHANISM Filed Oct. 26, 1951 2 Sheets-Sheet 1 Aug. 11, 1936. E. H. BICKLEY RADIO RECEIVER TUNING CONTROL MECHANISM 2 Shets-Sheet 2 Filed Oct. 26, 1931 Patented Aug. 11, 1936 PATENT OFFICE RADIO RECEIVER TUNING CONTROL MECHANISM v Everett Huckel Bickley, Bala-Gynwyd, Pa.

Application October 26, 1931, Serial No. 571,184

22 Claims.

This invention has to do with the art of radio receiver tuning control mechanisms, and more particularly that class known as pre-selection devices wherein some type of setting is made for 5 the stations available and some actuating or selecting mechanism, such as a knob, push-button or lever, is used to obtain the desired station, or change from station to station.

The present device seeks to avoid complications, both electrical and mechanical, by making use of the devices and mechanisms hereinafter disclosed. Radio tuning control devices heretofore have been constructed on what could be described as double acting principles. That is, the motive means having been built to operate in either direction, the tuning mechanism having come to a stop at the desired setting either from a lower frequency setting or a higher frequency setting ,as the case may be, duplicated the cus- 20 tomary hand operation. This introduced both electrical and mechanical complications, and added to the cost. The motor introduced radio interference, tended to drift past the proper set- ,ting, was slow to come up to speed, would not stop accurately at the point -desired, and went into oscillation when not perfectly adjusted. Ad-

justments in one direction would not hold for the other direction, and could not be maintained accurate.

In my device I-approach a setting always from the same side, use a spring motor, instead of an electric motor thus avoiding inertia eifects and slow starting, and provide a rigid stop for the positioning member thus insuring accuracy of setting and permanency of adjustment. Lost motion effects are eliminated as the forces are always acting in the same direction and are constantly alive.

In addition to the improved station selector, I have provided an automatic volume control which acts to give the same output within the capacity of the receiver for local or distant stations, an automatic motor rewind mechanism to wind up the spring above referred to when run down, a single station selecting mechanism, a program set up mechanism of novel construction, a simplified station indication, and a single knob control for volume and station selection. My device comprises a radio chassis of the conven- 50 tional form in which a single tuning control is provided to vary the frequency setting for the received signal. This tuning control is operated by my selector device to position it with a high degree of accuracy, as is required by the modem radio receivers. .A change from one station to the next is so quickly made that there is no pause apparent in the music if both stations are giving the same program.

Some of the objects of my invention in addition to those pointed out above are: to enable the user to quickly and simply set up the mechanism for automatic reception of any desired stations, to provide a positive indication of the position of the tuning mechanism for the reception of preselected stations, to provide automatic tuning and turning off of a radio receiver from a remote point with only a pair of wires, to eliminate noise and vibration from sudden stops, and motor commutation, to provide automatic tuning and turning off a radio receiver froma remote point with mechanical cable, wire or cord, to provide a clamp which can be removed or adjusted from the front with a single screw, to provide a noiseless escapement with front adjustments, to provide a supersimplified radio program selection mechanism, requiring no instructions for operation, and to provide all the above at a minimum of cost. 7

To make my invention clear, I have provided the following drawings,

Fig. 1 is a front view of a radio chassis embody'ing my invention.

Fig. 2 is a top view of the same with wiring diagram.

Fig. 3 is an enlarged view of the escapement and clamp.

Fig. 4 is a partial top view of the same.

Fig. 5 is a wiring diagram of the rewinding motor and connections.

Fig. 6 is an alternate construction top view of ,parts shown in Figs. 3 and 4 with'automatic volume control parts.

Fig. 'l is a front view of the same.

Fig. 8 is a modified form of escapement rect station selection.

Fig. 9 is a partial top view of the same.

Fig. 10 is a front view of a clock face with my program set up device incorporated.

Fig. 11 is a detailed view ofthe program selection key and associated parts.

Fig. 12 is an alternate form of the mechanisms shown in Figs. 8 and 9 arranged for electromagnetic operation, for remote control or program.

Fig. 13 is a detail of the stoplock.

Fig. 14 is a radio clock with the station indicating hand and flexible clock face.

Fig. 15 is a remote control box incorporating station selection and volume control. E

In greater detail, reference being had to ther for dinumerals in the figures, one number being used to designate a part wherever it appears, 5! is the radio chassis, 2 is the shaft controlling the tuning element or variable condensers, extending thru the front of the chassis. It is understood that at predetermined settings of this shaft the reception of broadcasting stations of various frequencies -is accomplished. The conventional dial divided usually from to 100 or from 550 to 1500 is replaced by the clamp carrier 3 which may or may not be calibrated in the conventional way. Around one half the edge of the clamp carrier 3 are provided gear teeth i; and the other half, a turned edge 5. The gear teeth l mesh with a pinion 6. This pinion is driven thru a throw out clutch (not shown) by the motor 3. A handle 8 is provided on the pinion 8 for manual tuning purposes. A plurality of clamps s are provided about the edge 5. These clamps are adjustably secured to the clamp carrier 3 by means of the screws in. On the surface of the clamp carrier 3 is provided a surface it adjacent to the clamps 9 for the purpose of marking the call letters of the broadcasting stations.

The line l2-l2 preferably indicates the center line of the radio chassis, midway of which is located the escutcheon or window E3 of the radio cabinet (not shown). Thus only a portion of the clamp carrier 3 is exposed at a time, and the call letters are caused to register perfectly in the window l3 by the adjustment of the clamp 9 and the restraint of the escapement stop l4, against the action of the spring l5. Around the shaft 2 is coiled the spring I5 one end being secured by suitable means to the shaft 2 and the other end is held by the stud H5 in the chassis front I. The tension of this spring i5 is adjusted so that all forces are overcome and when the escapement permits the tooth I! of the clamps 9 to pass, the clamp carrier 3 rotates until the next succeeding tooth I'I engages the hinged escapement stop l8.

This stop is cushioned by the rubber block l9 so that the impact forces are silently absorbed, and the clamp carrier '3 is brought to a stop after release without destructive jar or noise. The escapement stops l4 and I 8 are carried on the frame 20. This frame is mounted in the trunnions 2|, which in turn are suitably secured to the front of the chassis l. Adjusting screws 22 are provided in the ears 23 of the frame 20 to accurately set the position of the stops M and I8. A spring 24 under the left hand ear holds the escapement in the outer position with the rigid stop I 4 in position to engage the teeth IT on the clamps 9. Obviously any other escapement device adapted to seize a tooth or stop on the condenser moving member, which when operated by suitable means, allows a tooth to escape, may be used in lieu of the structure shown in Fig. 3.

A magnet coil 25 is mounted on the rear of the trunnion frame 2! in position so that the magnetism tends to act on the ear of the frame 23 to pull the escapement to the inner position. This releases the tooth l1 resting on the stop M and the clamp carrier 3 rotates under the action of the spring l5 until the next succeeding tooth engages the stop l8 which is now in position to receive it.

When the magnetism in the coil 25 is released the spring 24 causes the escapement 20 to assume the initial position thereby dropping the above mentioned tooth I! from the cushioned stop I8 to the rigid stop M. A battery 26 and switches or accuses contacts 2? are provided for energizing the mag net 25 thereby permitting the step by step tuning of the radio receiver i from a distance. The switch 2i may be provided with a ratchet indicator having the same number of ratchet positions as there are clamps on the clamp carrier 3 thus the indicator will. keep in step with the movements of the clamp carrier 3 and indicate at all times the station being listened to. If it is desired to operate manually, a button or mechanical cable or rod control may be used by suitable connection with the escapement 28 or the finger may be applied directly to the stop it to accomplish the desired tuning. After the full complement of clamps 3 have passed the escapement stop under the action of the spring 85 it is necessary to rewind the spring. This may be done manually by operating the knob 8 or automatically by means of the mechanism provided which will now be described.

on the clamp carrier 3 are provided two pins 28 and 23 extending backwards sufficiently to engage the lever 30 of the switch 3i at the extreme limit of motion of the clamp carrier 3. The switch 3i is secured to the front of the radio chassis I by the screws 38. The lever 30 is made of some insulating material, preferably bakelite, and is provided with two silver rivets 32. The friction joint holds the lever 30 on the insulating switch plate 3| so that it remains in either upper, lower or center position depending upon where it is positioned by the pins 28 or 29. In the upper position the silver rivet makes contact between the innermost contacts so that the circuit .is closed thru the battery 34 and the motor I so that the motor I is energized and rotates the clamp carrier 3 and shaft 2 thereby winding the spring I5.

It will be noted that the clamp teeth IT and the stops of the escapement l4 and I8 are chamfered or beveled so that no obstruction is offered to passage of teeth in the reverse direction, but the escapement is caused to oscillate back and forth as they pass.

.In order to prevent radio frequency interference in the radio receiver from the commutation or running of the motor and to provide an off position an additional pair of contacts 36 are provided on the switch 3| in series with the exciting current of the radio receiver, thus when the pin 29 operates the lever 30, the first action is to open the contacts 36 cutting the receiver dead. The clamp 3'! is adjusted with respect to the escapement, to stop the clamp carrier 3 in such a position that the pin 29.has moved the lever 30 to the center position. The next operation of the escapement causes the pin 29 to push the lever 30 to close the motor contacts 35 causing the rewind. When the pin 28 contacts the switch lever 30 the rewinding is complete and the motor circuit is broken and the radio receiver circuit is closed. The spring l5 now causes the clamp carrier 3 to rotate back until the first clamp tooth engages the stationary tooth on the escapement, and the adjustments are complete for the reception of broadcast on the frequency determined by the setting of the tuning elements mounted on the shaft 2.

The clamps may be adjusted around the edge of the clamp carrier 3 at any desired locations, and one clamp can readily be removed from between two clamps or additional clamps may be added at any time to accommodate other or additional stations.

The rewinding motor is preferably provided with a throwout clutch which operates to connect the motor rotor or armature after it reaches a predetermined speed. This allows the pinion B to run free of the rotor when the motor is not energized.

I do not limit myself to the exact constmction shown for the clamps and disc or clamp carrier, but these parts might be made in the form of aplurality of discs with suitable projecting teeth or notches, or many other inversions to accomplish the same result without departing from my invention. However, with the construction shown, an orderly compact arrangement with all adjustments accessible, is disclosed.

In order to accomplish automatic volume control, with individual control on each station, I have devised the following improved, construction shown in Figs. 6 and 7. An extension 39 is provided on the clamp front to hold the volume setting screw 40. This screw 40 is provided with a head 4| on which an adjusting wrench may be applied from the front. This head has a rounded portion adapted to contact with the pivoted shoe 42, a bracket is mounted on the front of the chassis l holding the shoe 42 so that the hump thereon contacts the screw head 4! when the tooth on the clamp properly rests on the rigid escapement stop i4. A spring 43 is interposed between the shoe 42 and the variable pressure resistance unit 44. The resistance of this resistor 44 varies depending upon the position of the adjusting screw 40, and is connected into a suitable circuit of the radio receiver to vary the volume. For instance it may be shorted across the voice coil of the speaker or it may be connected to vary the bias of the radio tubes, or it may be interposed at any other convenient point to accomplish the desired volume regulation. It is readily seen that each station can be adjusted for volume by the use of these screws 40, so that when adjusted all stations will come in at the same speaker volume. It has been found that this method of volume control is superior to automatic volume control by using an additional radio tube acting on the radio frequency tube biasing, in this respect. While the latter system tends to eliminate musical expression and interpretation by volume leveling during reception, the former system is not subject to this defect.

In order to set my device for operation the clamp carrier 3 is first turned manually using the knob 8, and the positions at which programs are received are marked on the clamp carrier noting the call letters of the stations received. The clamps 9 are then adjusted to these positions, making the final adjustment with the tooth i'i resting on the rigid stop i4. Each time the escapement Fig. 3 is operated by either the remote control magnet, or other means, .a new station will be tuned in. The volume control screws are now regulated until each station is received at the desired volume, in general a high level. An adjustment on the remote control rheostat will now affect all stations the same.

It may be desirable to tune directly to a wanted station, without going thru the seriesof stops. To accomplish this result my device is constructed as shown in Figs. 8, 9, and 12. 4| and 42 show my modified form of clamp on which-is provided a lug 43'. This lug 43' is located at a different place on each clamp as shown in Figs. 8 and 9, with the result that the lug on one clamp only is in position to contact the stop 44' on the setting lever 45' corresponding to the setting of the index 46 on the scale 41. The guide 48,

marking on the key 6|.

slots in the frame 50, and areso positioned as to aline with the positions of the lugs 43' respectively and, when any magnet is energized, the corresponding clamp will be engaged and the clamp carrier 3 will be correctly positioned for the indicated station. The springs 54 serve to return the a'rmatures 52 to their-inactive position when released by the lock 55. Whenever a new contact is made, the lock 55 releases the previously depressed stop bar, and looks down the last bar until a new contact is made. The spring 55 operates to hold the lock bar against the teeth 51 on stop bars 53. When it is desired to change stations automatically according to a predetermined schedule, I use the construction shown in Figs. 10 and 11, in which 58 is a clock dial having marked thereon the hours of the day and night, concentric with these figures are a plurality of key hole openings 59 corresponding to each fifteen minutes in the day and night, a plurality of keys 6!! are provided which may be inserted in the openings 59. These keys are made in sets (each set corresponding to a radio station) of several keys to a set. The keys are numbered or marked on the end 6| to indicate the station. A contact finger 62 is provided on each key, and the position of this contact is identical for all the keys in each set, but is different for each set. By inserting the proper key in the proper opening 59 a complete program for 24 hours may be set up in advance. A clock motor 53 is mounted on the back 0 the dial 58 by the screws 64. An hour hand 65 and minute hand 66 are provided and adjusted to move over the clock dial 58. A contacting lever B! is mounted on the rear end of the hour hand shaft of the clock motor 63. This lever carries a plurality of contacts 58 which are insulated from the lever itself but are adjusted to make contact with a plurality of insulated slip rings 69 on the inside, and the inwardly projecting fingers 62 of the keys 60 on the outside. These slip rings 69 respectively are part of the circuit of the magnets 51 respectively so that when the contact 68 closes the circuit thru the key 50 the proper magnet is energized to stop the radio tuning device in the position indicated by the The contacts 68 are adjusted to contact the fingers [52 at the same time as the hour hand points to the time indicated by the opening 59. An additional momentary series contact (not shown) operated from the minute hand shaft at 15 minute intervals is desirable v to make the timing more exact.

The operation is as follows: Assuming five clamps are properly set for receiving five stations, and one extra clamp is adjusted at the off position. The key sets No. 1 to No. 5 now represent these stations in sequence, the keys of set No. 6 being the off keys. Suppose it is .desired to listen to station WCAU from 4:30 p. m. to 6:15 p. m. then change to station WJZ until 7:30 p. m. then turn the set off. The key marked 2 is inserted in the keyhole corresponding to 4:30 p. m. as shown, another key, of set No. 4", is inserted in the keyhole at 6:15 p. m. and a key of set "No. 6" is inserted in the keyhole at 7:30 p. m. These stations will now ,be automatioally tuned in at the proper times, and the radio set will be turned off at 7:30 p. m.

When it is desired to combine a clock and radio set and to economize on space and manufacturing cost I prefer to use'the construction shown in' Figure 14. In this, it is the case, in which is mounted the radio chassis, loud speaker and clock motor. The face of the clock 73 made of thin material like parchment or grille cloth, is directly in front of the speaker, and the clock motor is suitably held in the center of the face by suitable braces from the case. The customary clock. numerals N are indicated on this face. The hour hand l5 and minute hand it are driven by the clock motor, in the usual manner. In addition to these hands I provide an additional shaft I8 and hand ll which is driven twice as fast as the tuning shaft 2 of the chassis l, by any suitable gearing or other suitable connections. Thus after a little time the user will become accustomed to the position of the hand ll for each radio station listened to and no other dial or indication means is required on the radio set. The remote control box i9 is provided with a variable resistance unit St adapted to be manually operated from the shaft 8i and knob 82. This resistance is connected into the radio circuit to vary the volume of the radio set. An extension 83 of the shaft 8i contacts with the spring contact 84. Opposed to this contact 86 is mounted another contact 85. Momentary pressure on the knob 82 will cause a momentary closure of the contacts 86 and 85. These contacts are connected into the circuit at 27 Fig. 2,

and the momentary closure above mentioned will act to change the station being listened to, or turn off the radio set, depending upon the position of the clamp carrier 3. An escapement is a mechanical construction which combines not only continuous interference to the passage of stops on a moving member past a point, but also includes, by the motion of the said interference, a means for the release of a restrained stop, while still presenting interference to the passage of a following stop.

I claim:

1. In a radio receiver tuning device, adjustable positioning members cooperatively associated with said tuning device for station settings, an escapement cooperating with said positioning members, a continuously acting means to force said positioning members against said escapement, a variable volume control associated with said positioning members and means in connection with said positioning members for setting the position of said variable volume control.

2. In a radio receiver, in combination, a tuning condenser, a dial mounted on said tuning condenser, adjustable stops on said dial, an escapement operating on said stops, and a spring acting on said tuning condenser and continuously urging the tuning condenser in one direction of rotation.

3. In a combination radio receiver and clock including a tuning mechanism; a face with time indicating numerals thereon, hands associated with said numerals for indicating time and a hand associated with the said numerals actuated by motions of said tuning mechanism, positioning stops on said tuning mechanism and escapement stops comprising a fixed stop and a yielding stop engaging said positioning stops to set said tuning device and said hand.

4. In a radio receiver, a tuning mechanism, a dial disc for indicating the position of said tuning mechanism, a plurality of removable positioning stops mounted on said disc, indicators on said stops to indicate the station settings, an escapement stop, and means impressing unidirectional torque on the disc to adapt the disc to bring the positioning stops into successive engagement with the escapement stop.

5. In a radio receiver including a tuning device. a volume control device and means for actuating said tuning device in one direction, adjustable positioning stops mounted in fixed relation with the moving member of said tuning device, an escapement, said stops contacting the escapement to position said tuning means, and adjustable means carried on said positioning stops for controlling said volume control device.

6. In a radio receiver, an automatic tuning device comprising adjustable positioning stops mounted in fixed relation with the moving member' of said tuning device, means for actuating said tuning device continuously in one direction, an escapement cooperating with said positioning stops for positioning said tuning device, rewlncling means for moving said tuning device in the opposite directic-n and a switch cooperating with said tuning device for preventing the operation of the receiver during said rewinding.

7. In a radio receiver tuning device, adjustable positioning members cooperatively associated with said tuning device for station settings, an

escapement cooperating with said positioning members comprising a fixed stop and a yielding stop to break the impacts on the fixed stop and means for unlatching said stops, and a continuously acting means to force said positioning members against said escapement stops for step by step tuning of said device.

8. In a radio receiver tuning control, a tuning device, a shaft operatively connected to the tuning device having a range of movement less than one complete shaft rotation, and, by its rotation, changing the tuning. spring means urging the shaft continuously in one direction of rotation, a plurality of stops rigidly connected to the shaft and adjustable in their spacings from one another, an escapement stop engaging said stops successively and determining the position of the shaft in rotation and means for releasing the escapement stop and permitting the spring means to rotate the shaft until a succeeding stop is engaged by the escapement stop, whereby the tuning changes step by step.

9. In a radio receiver tuning control, a tuning device, a shaft operatively connected to the tuning device having a range of movement less than one complete shaft rotation, and, by its rotation,

changing the tuning, spring means urging the' shaft continuously in one direction of rotation, a plurality of stops rigidly connected to the shaft and adjustable in their spacings from one another, an escapement stop engaging said stops succes- 'sively and determining the position of the shaft in rotation, an electromagnet operatively connected to the escapement stop and an electric circuit including the electro-magnet, a source of electrical energy and a switch, whereby making contact at the switch operates the escapement stop and permits the spring means torotate the shaft until the next stop is engaged by the escapement stop.

10. In a radio receiver set, a shaft, a tuning disc thereon, a spring impressing a torque on the disc, a plurality of stops peripherally adjustable on the disc having operating engagement surfaces spaced from one another angularly with respect to the shaft axis, an escapement adapted in cooperating with the spring to intermittently operate on and release the stops one after the other, a wind-up mechanism for the spring, angularly retracting the disc in a direction reverse to that of the torque, first and second. electric circuits adapted to operate respectively the radio and the wind-up mechanism, a switch operatively associated with the disc closing the first and second circuits at respectively opposite ends of its throw and opening both circuits in an intermediate position, and switch-throwing projections on the disc located to engage and operate the switch in opposite directions at the opposite ends of the range of movement of the disc, one projection moving the switch to its intermediate position to open the radio circuit as the disc moves the last stop into engagement with the escapement, and to close the wind-up circuit when the escapement releases the last stop, and the other projection operating during the end portion of the wind-up to successively open the wind-up circuit and close the radio circuit.

11. In a radio receiver set, a shaft, a tuning disc thereon having complementary semi-peripheral portions, a, series of stops on the disc spaced along one of the said portions, a spring impressing a torque on the disc, an escapement adapted in cooperation with the spring to engage and release the stops intermittently, one after the other, and a wind-up mechanism for angularly retracting the disc in a direction reverse to that of the torque and said mechanism having a rolling engagement with the disc along the other of. said peripheral portions.

12. In a radio receiver tuning control, a tuning device, a shaft operatively connected to the tuning device, having a range of movement less than one complete shaft rotation, and, by its rotation, changing the tuning, spring means urging the shaft continuously in one direction of rotation, a plurality of stops rigidly connected to the shaft and adjustable in their spacings from one another, an escapement stop engaging said stops successively and determining the position of the shaft in rotation, means for releasing the escapement stop and permitting the spring means to rotate the shaft until succeeding stop is engaged by the escapement stop and means automatically operative when the shaft has reached its limit of. rotation in said one direction for rotating the shaft in the opposite direction against the action of the spring means until the shaft reaches its limit of rotation in the opposite direction.

13. In a radio receiver tuning control, a tunmg device, a shaft operatively connected to the tuning device, having a range of movement less than one complete shaft rotation, and, by its rotation, changing the tuning, spring means urging the shaft continuously in one direction of rotation, a plurality of stops rigidly connected to the shaft and adjustable in their spacings from one another, an escapement stop engaging said stops successively and determining the position of the shaft in rotation, an electro-ma'gnet operatively connected to the escapement stop, an electric circuit including the electro-mag'net, a source of electrical energy and a switch and means automatically operative when the shaft has reached its limit .of rotation in said one direction for rotating the shaft in the opposite Y direction against the action of the spring means the opposite direction.

until the shaft reaches its limit of rotation in 14. In a radio receiver tuning control, a tuning device, a shaft operatively connected to the tuning device, having a than one complete rotation, and, by its rotation, changing the tuning, spring means urging the shaft continuously in one direction of rotation, a plurality of. stops, rigidly connected to the shaft and adjustable in their spacings from one another, an escapement stop engaging said stops successively and determining the position of the shaft in rotation, means for releasing the escapement stop and permitting the spring means to rotate the shaft until a succeeding stop is engaged by the escapement stop, an electric motor operatively connected to the shaft for rotating the shaft in the opposite direction against the action of.the spring means, automatic means effective when the shaft reaches its limit of rotation in said one direction for operating the electric motor and automatic means for disconnecting the radio set when the electric motor is in operation and reconnecting the radio set when the electric motor ceases operation.

15. In a radio receiver tuning control, a tuning device, a shaft operatively connected to the tuning device, having a range of movement less than one complete rotation, and, by its rotation, changing the tuning, spring means urging the shaft continuously in one direction of rotation, a plurality of stops, rigidly connected to the shaft and adjustable another, an escapement stop engaging said stops successively and determining the position of the shaft in rotation, an electro-magnet operatively connected to the escapement stop, an electric circuit including the electro-magnet, a source of electrical energy and a switch, an electric motor operatively connected to the shaft for rotating the shaft in the opposite direction against the action of the spring means, automatic means ef.- fective when the shaft reaches its limit of rotation in said one direction for operating the electric motor and automatic means for disconnecting the radio set when the electric motor is in operation and reconnecting the radio set when the electric motor ceases operation.

16. In a radio receiver tuning control, a tuning device, a shaft operatively connected to the tuning device and, by its rotation, changing the tuning, spring means urging the shaft continuously in one direction of rotation, a plurality of stops rigidly connected to the shaft an escapement device engaging said stops successively and determining. the position .of the shaft in rota-' tion, comprising-a yieldable member which receives the inffl'ai'shock of. stopping rotation and U a .rigid member, means for releasing the escapement device and permitting the spring means to rotate the shaft until a succeeding stop is engaged by the yieldable member and means for releasing the yieldable member and permitting said stop to engage the rigid member.

1'7. In a radio receiver tuning control, a tuning device, a shaft operatively connected to the tuning device and, by its rotation, changing the tuning, spring means urging the shaft continuously in one direction of rotation, a plurality of stops rigidly connected to the shaft, an escapement device engaging said stops successively and determining the position of the shaft in rotation, comprising a yieldable member which receives the initial shock of stopping rotation and a rigid member, an electro-magnetic device operatively range of movement less in their spacings from one connected to the escapement device, bringing the yieldable member into latching position when. the electro-magnetic device is energized and bringing the rigid member into latching position and the yieldable member out of latching position when the electro-magnetic device is de-energized and an electric circuit including the eleotro-magnetic device, a source of electrical energy and a switch.

18. In a radio receiver tuning device, a variable volume .control, a tuning dial associated therewith, yieldable means exerting a turning torque thereon, an escapement associated with the dial, a series oi stops mounted on the dial for individual engagements with the escapement to position the dial at diflerent settings thereof, and ad-- Justable means on each stop to adjustably set the volume control while the stop engages the escapement.

19'. In a radio receiver control mechanism, a tuning device, a shaft operatively connected to the tuning device and, by its rotation, changing the tuning, spring means urging the shaft continuously in one direction of rotation, a plurality of stops mounted upon the shaft, a volume control member associated with each stop, an escapement stop engaging said stops successively and determining the position of the shaft in rotation, means for releasing the escapement stop and permitting the spring means to rotate the shaft until a succeeding stop is engaged by the escapement stop and a volume control operated by the successive volume control members as the stops are engaged by the escapement stop, whereby, for any given station tuned in, the appropriate volume control adjustment is automatically obtained.

20. In a radio receiver control mechanism, a tuning device, a shaft operatively connected to the tuningodevice and, by its rotation, changing the tuning, spring means urging the shaft continuously in one direction of rotation, a plurality of stops mounted upon the shaft, a volume conaccents trol member associated with each stop, an escapement stop engaging said stops successively and members as the stops are engaged by the escapement stop, whereby, for any given station tuned in, the appropriate volume control adjustment is automatically obtained.

21. In a radio receiver control means for releasing the escapement stop and permitting the spring means to rotate the shaft until pressure exerted by the successive volume control members as the stops are engaged by the escapement stop, whereby, for any given station tuned in, the appropriate volume control adjustment is automatically obtained.

22. In a radio control device, a gauged receiving tuner tuned by rotation of a single tuning shaft, spring means urging the shaft continuously in one direction of rotation, selective stops angularly distributed about the shaft for limiting the shaft rotation, a

of the shaft, and switching means controlling the operation of said motor, actuated by said shaft.

H. BICKLEY. 

